Inverted siphon drain for tank roofs



June 20, 1944. J. H. WIGGINS INVERTED SIPHON DRAIN FOR TANK ROOFS FiledFeb. '15, 1943 IN VEN TOR JOHN H. WlGG/NS Patented June 20, 1944 UNITEDSTATES PATENT QFF'ICE INVERTEl) SIPHON DRAIN FOR. TANK ROOFS John H.Wiggins, omea o, Ill. Application February 15, 1943, Serial No. 475,927-

(c1.'1s2 v-) Claims.

This invention relates to drains for removin water from the roofs or topof gas and/or liquid storage tanks, and particularly inverted siphondrains for floating roofs and breather type roofs of the kind -now usedextensively on tanks in which gases, gasoline and crude oilare stored.

One objectionable feature or characteristic of the conventional tankroof inverted siphon drain is that it cannot be cleaned, inspected, orre.- paired while the tank is in normal operation, due to the fact thatpartsof the drain which are located on the underside of the roof are notaccessible until after a screw-threaded joint has been disconnectedsoastoenable the parts of the drain to be drawn upwardly through anopening in the roof.

The main object of my invention is to provide an inverted siphon roofdrain of novel construction whose'partsare accessible from the top sideof the roof for inspection, cleaning, or replacement, when the tank isinnorm'al operation, i. e., in the case of a floating roof when the roofis supported by or floating on the liquid in the tank, and in the caseof a breather type roof, when the tank is under pressure.

-Another object'is to provide a tank roofinverted siphondrain," in whichwater may safely be used to constitute the liquid sealing medium of thedrain, due to the fact-that the drain is of such construction or designthat at freezing temperatures the sealing Water-can freezesol-id;without breaking or cracking-the parts of the drain,

and when the temperature moderates, said-water will melt and againfunction as a liquid sealing medium for-the drain And stillanotherobject ofmy invention is-to provide a tank roof inverted drainthat is equipped with a removable sealing member or balfle, andmeanswhereby the operation of removing said sealing member automaticallycloses the discharge pipe or outlet or the drain, and the operation ofrestoring said sealingmember automatically opens said discharge pipeoroutlet.

Other objects and desirable features of my invention will be hereinafterpointed out.

. Figure l of the. drawingis-a. fragmentary top plan view of a. floatingtank roof equipped with my improved drain, showing the draininhorizontal sectionon theline 1-! of. Figure 2.

Figure .2 is a vertical sectional. view of said drain,.taken on the line2:-2'of Figure 1; and

, Figure 3 is a diagrammatic view, illustrating in transverse.cross-section,- the tank,-=the floating roof, and the drain whichremoves rain or-snow waterirom the .top side ointhe rooft In Figure 3 ofthe drawing, A designates a-tank that is used to store-gasoline or oil,and B desi nates a floating roof thatis adapted-to cover and besupported by the gasoline oroil a: in said tank.

- My invention consists of a double inverted siphon drain that is usedto'carry off rain water or snow water from the top side of the roof Band discharge said water downwardly into the oil 1' in the tank A. Saiddrain comprises a receptacle or tub C carried by the roof'B and arrangedso that water which falls onor-collects on the roof can flow or draininto. the open upper end of said receptacle, a tubular outlet ordischarge pipe D at the lower end of the receptacle C through whichwater escapes from-- said receptacle and flows downwardly into the bodyof-oil a: on which the roof floats, anda sealing'member or baffle Eremovably mounted in the receptacle C and 'accessible from the top sideof the roof, the lower end portion of said baflie E being submerged in aliquid sealing medium y in the receptacle C.

As shown in Figures 1 and 2, the receptacle C, which is tub-shaped ingeneral form or outline, tapers inwardly from its upper to its lowerend, and is rectangular-shaped in horizontal cross section, saidreceptacle being-provided at itsupper end with a laterally-projectingflange I that is attached to the roofB in concentric relationship with adrain hole. 2 in said'roof. The outlet or discharge pip D of the drainis formed by an open-ended, vertically-disposed, tubular member that isrigidly attached to the bottom 3 of the receptacle C, the upper end ofsaid discharge pipe terminating some distance above the bottom 3 of saidreceptacle. The sealing member or bafile E is removablymounted. in thereceptacle C, and is arranged between the inlet at the upper end of saidreceptacle and the-discharge pipe or outlet D of the. drain. Said baffleor sealing member E conforms approximatelyto the shape of the side wall4 of the. receptacle-C and is so proportioned with relation to saidreceptacle, that when said baffle E is in its operative: position, shownin Figure 2, there is a tall, relatively narrow slot or space betweenthe side Wall 4 of the receptacle C and the side wall portion of saidbafile. The open lower end of the baffle E is maintained in spacedrelationship with the bottom 3 of the receptacle C by any-suitablemeans, such, for example, as by legstizat the lower end of the side wallportion of the baflleE, Whenrny improved drain is designed for use on afloating tank roof, it is not necessaryth'at' the upper end of thetubular baflle or-seal-ing-member E beclosed, but

55, inorder to reduce evaporation losses; I prefer to arrange aremovable cover or closure F in the upper end portion of the baflie E.The removable closure F, shown in Figure 2, preferably has a sliding fitwith the upper end portion of the sealing member E and is made ofrelatively great length or depth, so as to minimize evaporation losses.

Before. the tank is filled with oil, gasoline or other liquid, a liquidsealing medium 11 preferably water, is introduced into. the receptacleC, so as to fill the lower. end portion of said receptacle up to the topedge or upper end of the outlet or discharge pipe D of the drain.Thereafter, the baffle or sealing member E is introduced into thereceptacle.C, so as to form 'a' baflie between the discharge pipe D andthe it can be cleaned, inspected, or repaired, in the case of a floatingroof, while the roof is floating on the liquid in the tank, and in thecase of a breather type roof while the tank is under pressure. All thatis necessary in the event inspection, cleaning or repair of the drainbecomes necessary, is to close the outlet or discharge pipe D of thedrain and then lift the baflie or sealing member E upwardly out of thereceptacle C. Various means can be usedto close the discharge pipe Dwhenthe baflieE is .to be removed. One means that can be employed forthis purpose, is

any suitable kind of a plug that can be inserted in the upper end of thedischarge pipe D, after suflicient oil has been introduced intothe tankto cause the roof B to start to float, oil will flow upwardly throughthe discharge pipe D of the drain and fill-theupperv portion of thesealing member Eabove the level of the liquidsealing medium y,therebydepressing or lowering the level ofthe columnofseafing Water inthe space between the discharge pipeD and the side wall portion of thebaflleE, and raising or increasing the level of the column of sealingwater in the space between the side wall portion of the bafiie E and thesidewall 4 of the receptacle C. By the time sufficient oil has beenintroduced, into the tank to float the roof B, or-cause said roof tobeentirely supported by the-oil in the tank- A, the column formedbytheysealing water balancesthe lighter specific-gravity. oil, and theliquid sealing-medium y remains in substantially the positionshown inFigure 2, wherein the heavy horizontal lines y designatethe liquidsealing medium, and the lighter horizontal broken lines designated bythe reference character :0, represent the oil from the tank thathas-backed'up into the .bailie E through the discharge pipe D and whichfloats on the liquidsealing medium 3! that previously wasintroduced intothe receptacle C. At the firstrain, the rain water escapes from the topside of the roof andenters the space or slot between the side .wall 4 ofthe receptacleq and the side wall portion of the baille E, therebycausing the sealing water y in the space between the discharge pipeD andthe side Wall, portion of said baflle to rise, with the result that someof thewater overflows the top edge of the discharge pipe D and escapesdownwardly through same into the body of oil on which the roof floats.The area of. thespace between the discharge pipe D and the side wallportion of; the baffle E is preferably madethree or fourtimes the areaof the narrow slot between the sidewall 4 of the receptacle C, and-theside wall portion of the baflie E, so that one inch of evaporation (say,during a long dry spell) from the watersurfacein said narrow slot, willusually be only one-third to one-fourthof the replenishing supply ofwater in the space between the discharge pipe D and the-side wallportion of the bailleE- 1 H One of themain advantages of my improveddrain is that it permits water to be used as the liquid sealing mediumof the drain, because the thin column of water in the tall, narrow,tubular space between the baflle and'the, side wall 4 of the receptacle0 and the shallow puddle of water in the space between the baffle andthe discharge pipe D, can freeze solid without danger of breaking orcracking the co-acting parts of the drain.

the cover F of the sealing member E has been removed and preparatory towithdrawing the sealing member E from the receptacle C. I pre- 'fer,however, to mount a valve or closure G on Another desirable featureofthe drain, :is; that the upper end portion of the discharge pipe D, andprovide means for causing said valve to close automatically when thebaiiie E is removed, and to open automatically when the bafile E isreplaced in the receptacle C. As shown in Fig:- ures 1 and 2, a weightedvalve or closure G, that ispivotally mounted on the upper end portion ofthe discharge pipe D, is provided with a lat-, erally-projecting arm 6.An actuating device 1, that is carried by the baffle E, is soarrangedthat when said bafile is moved downwardly into the receptacle0,- the actuating device I will engage the arm 6 of the valve G,- andmove said valve upwardly into its open position, shown in Figure; 2.'When the baiile E is withdrawn from the receptacle C, the actuatingdevice-1 will be dis-; engaged from the arm 6 of the valve-G, and saidvalve will then drop into its closed position, thus closing the outletor discharge pipe D of the drain. All of the above described operationscan be performed from the top side of thereof B when the roof isfloating on the liquid in the tank. When my improved valve is intendedto be used one. breather type roof, it is necessary to use asubstantially inverted, cup-shaped sealing member or baflle, or, inother words, a seal-. ing member whose upper portion is gas-tight; InFigure 4 of the drawing I have illustrated a drain designed for use witha breather type roof.-

In general construction,it is similar to the drain shown in Figure 2,except that the removable sealing member or baflle E is provided withagas-tight head orupper end F'. The-side wall portion of the receptacle Cis attached tothe roof B, so that its upper end terminates above the topside of the roof, thus causing waterf to' 1. A siphon drain, comprisinga receptacle dis posedso that drain water will enter the upper end ofsaid receptacle, the side' wall portion of said receptacle slopingoutwardly from its I lower towards, its upper end, avertically-disposed"dutlet or discharge pipe for said receptacle havingits upperhendterminating at a'point above the bottom-ofsaidreceptacle,.said receptacle being adapted to contain a liquidsealing medium when the drain is in use, and; a baflie of substantially;the same shape as z'the: sidewall portion iof.;the'

a relatively tall, narrow slot having a width ap-' proximately one-thirdthe width of the annular space between the battle and the discharge pipeof the receptacle.

3. A drain of the kind described in claim 1,

in which the discharge pipe is provided with a valve, and meanscontrolled by the bafile for opening and closing said valve.

4. A drain, comprising a receptacle disposed so that water can drain orflow into the upper end of said receptacle, an outlet or discharge pipein the bottom of said receptacle, projecting upwardly' into same andterminating at a point above the bottom of said receptacle, saidreceptacle being adapted to contain a liquid sealing medium when thedrain is in use, a bafile or sealing member removably mounted in saidreceptacle between said discharge pipe and the side wall of thereceptacle and arranged with its lower end portion submerged in theliquid sealing medium and spaced away from the bottom of saidreceptacle, and a valve for closing said discharge pipe when the bafileis removed.

5. A drain of the kind described in claim 4, having provision forcausing said valve to close automatically when the baflle is removed andfor opening said valve automatically when-the baffle is replaced in saidreceptacle.

JOHN H. WIGGINS.

